Two military personnel have been shot near the White House in Washington DC.
A suspect has been taken into custody and the area secured, police said.
The White House was placed into lockdown, while US President Donald Trump is away in Florida.
Mr Trump posted on his Truth Social platform to say the two National Guard members had been “critically wounded”, adding that the “animal” that shot them “is also severely wounded, but regardless, will pay a very steep price”.
Both guardsmen were shot in the head, according to Sky’s US partner network, NBC News, quoting an official and a senior official directly briefed on the investigation.
The shooting will be investigated by the FBI as a possible act of terror, two senior US law enforcement officials told NBC.
The suspect, who used a handgun in the attack, has been initially identified as an Afghan national, the officials said.
But investigators are still trying to confirm all of the individual’s details.
West Virginia’s governor initially said both victims were members of his state’s National Guard and had died from their injuries – but later posted to say there were “conflicting reports about the condition of our two Guard members”.
Patrick Morrisey had said: “These brave West Virginians lost their lives in the service of their country.”
Image: Pic: AP
FBI director Kash Patel said two National Guard members were “brazenly attacked in a horrendous act of violence”.
At a news conference he clarified they were in a “critical condition”.
Jeff Carroll, chief of the metropolitan police department in the area, said the attack began at 2.15pm local time (7.15pm in the UK) while National Guard members were on “high visibility patrols in the area”.
He said: “A suspect came around the corner, raised his arm with a firearm and discharged it at the National Guard.
“The National Guard members were… able to – after some back and forth – able to subdue the individual and bring them into custody.”
Washington DC mayor Muriel Bowser called the attack a “targeted shooting”.
Image: Pics: AP
Social media footage showed first responders attempting CPR on one of the soldiers as they treated the other on a pavement covered in glass.
Nearby other officers could be seen restraining an individual on the ground.
Image: Emergency personnel cordon off an area near where the National Guard soldiers were shot. Pics: AP
The scene has been cordoned off by police tape, while agents from the US Secret Service and Bureau of Alcohol, Tobacco, Firearms and Explosives were on the scene, as National Guard troops stood sentry nearby. The FBI was also on the scene, the agency’s director said.
The Joint DC Task Force confirmed it was responding to an incident in the vicinity of the White House.
The DC Police Department posted on X: “Critical Incident: MPD is on the scene of a shooting at 17th and I Street, NW. Please avoid the area.”
In an update, the force said: “The scene is secured. One suspect is in custody.”
White House press secretary Karoline Leavitt said: “The White House is aware and actively monitoring this tragic situation.
“The president has been briefed.”
Mr Trump was at his resort in Palm Beach ahead of the Thanksgiving holiday, while US vice president JD Vance was in Kentucky.
US defence secretary Pete Hegseth said Mr Trump had asked for 500 more troops to be deployed to Washington DC after the shooting.
Flights arriving at Ronald Reagan Washington National Airport were temporarily halted due to its proximity to the scene of the shooting, the US Federal Aviation Administration said.
Hundreds of National Guard members have been patrolling the nation’s capital after Mr Trump issued an emergency order in August, which federalised the local police force and sent in the guard from eight states and the District of Columbia.